java (beginner) converting scientific notation to decimal

Question

if

double d =  1.999e-4

I want my output to be 0.0001999.

How can I do it?

You should select an answer and/or upvote answers that were helpful. — jahroy, Oct 25 '12 at 21:18

score 9 · Accepted Answer · answered Oct 25 '12 at 08:33

9

NumberFormat formatter = new DecimalFormat("###.#####");  

String f = formatter.format(d);

You can explore the sub classes of NumberFormat class to know more details.

answered Oct 25 '12 at 08:33

RP-

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score 5 · Answer 2 · answered Oct 25 '12 at 08:35

You can do it like this:

    double d = 1.999e-4;
    NumberFormat nf = NumberFormat.getInstance();
    nf.setMinimumFractionDigits(7);
    System.out.println(nf.format(d));

Check out the documentation of NumberFormat's methods to format your double as you see fit.

DecimalFormat is a special case of NumberFormat as its constructor states, I don't think that you need its functionality for your case. Check out their documentation if you are confused. Use the factory method getInstance() of NumberFormat for your convenience.

Thank you very much! (BTW NumberFormat and DecimalFormat which one should I use??) — hibc, Oct 25 '12 at 08:37

score 5 · Answer 3 · edited Jul 08 '15 at 14:32

5

I suppose there is a method in BigDecimal Class called toPlainString(). e.g. if the the BigDecimal is 1.23e-8 then the method returns 0.0000000124.

BigDecimal d = new BigDecimal("1.23E-8");

System.out.println(d.toPlainString());

Above code prints 0.0000000123, then you can process the string as per your requirement.

edited Jul 08 '15 at 14:32

himawan_r

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answered Jul 08 '15 at 13:56

Harsh Chaturvedi

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my excelsheet number is 42.063706, but returns 42.06370600000000337104211212135851383209228515625 – Abdullah Nurum Feb 26 '18 at 18:08
@AbdullahNurum what method are you using to read in the excel sheet and construct the BigDecimal object? When I construct it with the string literal "42.063706" it outputs the correct thing (same as input). Make sure you aren't storing it in a floating point value in between reading and making the BigDecimal object. You should keep it as a string during that time, in order to not lose precision. – theferrit32 May 29 '19 at 23:51

score 3 · Answer 4 · answered Oct 25 '12 at 08:36

3

If all you want is to print like that.

System.out.printf("%1$.10f", d);

you can change 10f, 10=number of decimal places you want.

answered Oct 25 '12 at 08:36

specialscope

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Thank you very much! what does 1$ = ?? – hibc Oct 25 '12 at 08:39
1$=argument index, if you had System.out.printf("%3$.10f", e,f,d); you would use 3$ as your target is d. Details here. http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Formatter.html – specialscope Oct 25 '12 at 09:02

score 0 · Answer 5 · answered Oct 25 '12 at 08:31

0

Take a look over

java.text.DecimalFormat

and

java.text.DecimalFormatSymbols

answered Oct 25 '12 at 08:31

cmg_george

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java (beginner) converting scientific notation to decimal

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